Investigation of methylated polyethylenimine halide salts exhibiting upper critical solution temperature (UCST) phase transition in aqueous solution

Minwoo Noh,Yan Lee 한국고분자학회 2016 한국고분자학회 학술대회 연구논문 초록집 Vol.41 No.2

Upper critical solution temperature (UCST) phase transition of halide salts of branched polyethylenimine and methylated branched polyethylenimine in aqueous solutions

Noh, Minwoo,Kang, Sunah,Mok, Yeongbong,Choi, So Jung,Park, Jeongseon,Kingma, Jannick,Seo, Ji-Hun,Lee, Yan The Royal Society of Chemistry 2016 Chemical communications Vol.52 No.3

<P>The upper critical solution temperature (UCST) phase transition of halide salts of branched polyethylenimine (PEI) and methylated branched polyethylenimine (MPEI) is first reported in aqueous solutions. In particular, iodide counter-ions can introduce UCST properties in MPEI. The importance of the counter-ion composition of MPEI for UCST transition is discussed in detail.</P>

Novel lower critical solution temperature phase transition materials effectively control osmosis by mild temperature changes

Noh, Minwoo,Mok, Yeongbong,Lee, Seonju,Kim, Heejin,Lee, So Hyun,Jin, Geun-woo,Seo, Ji-Hun,Koo, Heebeom,Park, Tae Ha,Lee, Yan The Royal Society of Chemistry 2012 Chemical communications Vol.48 No.32

<P>Osmosis can be controlled reversibly and effectively by mild temperature changes based on novel thermosensitive solutes with LCST transition. The <I>n</I>Bu-TAEA thermosensitive solution can draw fresh water from seawater at temperatures less than the phase separation temperature, and the osmotic flow was reversed at higher temperatures.</P> <P>Graphic Abstract</P><P>Osmosis can be controlled reversibly and effectively by mild temperature changes based on thermosensitive solutes with LCST transition. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c2cc30890h'> </P>

Ternary blend organic solar cells with improved morphological stability

Nam, Minwoo,Yoo, Jaehong,Park, Yunjae,Noh, Hye Yeon,Park, Yongkook,Cho, Junhee,Kim, Jung-A.,Kim, Jehan,Lee, Hyun Hwi,Chang, Rakwoo,Ko, Doo-Hyun The Royal Society of Chemistry 2019 Journal of Materials Chemistry A Vol.7 No.16

<P>Long-term stability of organic blends is a key factor for the practical use of organic solar cells (OSCs) in commercial fields. Here, we report the strategic incorporation of non-fullerene small molecules in polymer:fullerene blends to obtain ternary OSCs with improved efficiency and extended lifetimes. Non-fullerene small molecules employed in the polymer:fullerene blend successfully increased the photon-to-current conversion process as an efficient charge cascade acceptor. A combination of theoretical simulations and experimental measurements revealed that aggregation of meta-stable fullerene molecules was significantly alleviated in the ternary blend, thereby preventing an unintentional increase in the threshold for charge transfer during operation. Thus, the ternary OSCs could exhibit highly extended lifetimes with improved morphological stability and better resistance to performance decay under harsh real operational conditions compared to their binary counterparts. Combined with its high efficiency and improved device lifetimes, the high tolerance to the ternary blend thickness offers promise for commercially acceptable ternary OSCs fabricated by a printing process.</P>

Curve Fitting을 이용한 건설장비 CO₂ 배출량 예측 모델

노재윤 ( Noh Jaeyun ),김유진 ( Kim Yujin ),이지연 ( Lee Jiyeon ),이민우 ( Lee Minwoo ),한승우 ( Han Seungwoo ) 한국건축시공학회 2020 한국건축시공학회 학술발표대회 논문집 Vol.20 No.1

The severity of the global climate crisis is increasing due to greenhouse gases caused by human activities. As a result, countries and industries are making efforts to reduce carbon dioxide emissions, the biggest cause of global warming. Many studies have been conducted to predict carbon emissions in the construction sector to reduce this, but they have not actually produced a highly usable formula in the field. Therefore, the two variables 'Curve Fitting' were performed based on the data of excavators and trucks measured at the field. As a result, we have obtained a carbon dioxide emission prediction model for construction equipment, and we would like to use it to help establish an eco-friendly process plan.

Semi-transparent quaternary organic blends for advanced photovoltaic applications

Nam, Minwoo,Noh, Hye Yeon,Kang, Joo-Han,Cho, Junhee,Min, Byoung Koun,Shim, Jae Won,Ko, Doo-Hyun Elsevier 2019 Nano energy Vol.58 No.-

<P><B>Abstract</B></P> <P>In spite of enormous promise in a multitude of applications, semi-transparent organic photovoltaics (ST OPVs) relatively lag behind opaque OPVs in the efficiency, and further efforts are imperative to improve their performance while preserving their transparency and tunable color perceptivity. Here, we develop highly efficient ST OPVs based on quaternary blends (Q-blend) involving non-fullerene small molecules, and demonstrate their realistic application in four-terminal (4T) tandem PVs. The ST quaternary OPV (Q-OPV) exhibits superior power conversion efficiencies (PCEs) higher than those of the state-of-the-art ST OPVs under any irradiation conditions, while retaining high transparency and the possibility of implementing various colors. In particular, we achieve the first PCE value exceeding 15% (~15.46%) under indoor lighting among the ST OPVs reported to date. The 4T tandem configurations based on a ST Q-OPV with diverse opaque PVs demonstrate broadband photon harvesting, with aesthetic functions rendered from the color-codable ST Q-OPV. The benefits of the Q-blend platform, including efficient operation under any irradiation circumstance (both indoor and outdoor lighting) and device color codability via tuning the quaternary components, can further expand the applicability of the ST Q-OPV to various practical applications.</P> <P><B>Highlights</B></P> <P> <UL> <LI> We demonstrate semi-transparent quaternary organic photovoltaics (ST Q-OPVs) for advanced photovoltaic applications. </LI> <LI> The ST Q-OPV is used in four-terminal tandem systems to accommodate an enhanced spectral response and aesthetic functions. </LI> <LI> The benefits of tunable color and efficient operation under any irradiation conditions expand the utility of the ST Q-OPV. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Host–Guest Chemistry of 1D Suprachannels and Dihalomethane Molecules: Metallacyclodimeric Ensembles Consisting of Zinc(II)-2,7-bis(nicotinoyloxy)naphthalene Complexes

Park, Minwoo,Kim, Hyeun,Lee, Haeri,Noh, Tae Hwan,Jung, Ok-Sang American Chemical Society 2014 Crystal Growth & Design Vol.14 No.9

<P>Self-assembly of ZnX<SUB>2</SUB> (X = Cl, Br, and I) with 2,7-bis(nicotinoyloxy)naphthalene (L) as a hemicircular bidentate ligand containing a chromophore moiety yields a systematic metallacyclodimeric unit, [ZnX<SUB>2</SUB>(L)]<SUB>2</SUB>. These basic skeletons constitute, via interdigitated π···π interactions, a unique columnar ensemble forming a suprachannel. This can then be employed as an unusual “diiodomethane within the suprachannel” host–guest system, CH<SUB>2</SUB>I<SUB>2</SUB>@[ZnX<SUB>2</SUB>(L)]<SUB>2</SUB>. Specifically, the suprachannel significantly stabilizes the CH<SUB>2</SUB>I<SUB>2</SUB> molecules in the order [ZnI<SUB>2</SUB>(L)]<SUB>2</SUB> > [ZnBr<SUB>2</SUB>(L)]<SUB>2</SUB> > [ZnCl<SUB>2</SUB>(L)]<SUB>2</SUB>. This suprachannel has significant halogen effects on the photoluminescence (PL), thermal properties, and host–guest inclusion.</P><P>Suprachannels consisting of zinc(II) metallacyclodimers through the unique interdigitated columnar π···π interactions along with their significant halogen effects on the host−guest inclusion, photoluminescence (PL), and thermal properties were investigated.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/cgdefu/2014/cgdefu.2014.14.issue-9/cg5009889/production/images/medium/cg-2014-009889_0007.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/cg5009889'>ACS Electronic Supporting Info</A></P>

Light-tunable thermoresponsive behavior of branched polyethylenimine derivatives in water

Mok, Yeongbong,Noh, Minwoo,Chan Kim, Gyu,Song, Youngjun,Kim, Heejin,Kim, Seulah,Yi, Sihyeong,Seo, Ji-Hun,Lee, Yan Elsevier 2016 Polymer Vol.107 No.-

<P><B>Abstracts</B></P> <P>Combinatorial introduction of acyl, alkylsulfonyl and azobenzene (Ab) functionalities into amine-rich branched polyethylenimine produces dual-signal-responsive polymers with both temperature- and light-responsiveness in aqueous solutions. Light-tunable L/UCST polymers were synthesized by simple introduction of acyl and Ab groups or alkylsulfonyl and Ab groups, respectively. The phase transition temperatures of the polymers were dependent upon the ratios of the functionalities and reversibly controlled by light irradiation. More than 35°C-shift of the LCST was obtained by UV-irradiation, which is the largest shift reported in water. Moreover, 19°C-shift of the UCST was obtained by UV-irradiation, which is the first UCST shift reported in polymer–water binary systems.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Simple and efficient synthetic methods for producing dual-signal-responsiveness. </LI> <LI> The largest shifts of phase transition temperature upon irradiation. </LI> <LI> The first report of light-induced UCST shift in polymer-water binary system. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

미래 기후변화를 고려한 보령댐 비상도수시설 운영방안 연구

임건묵(Lim, Gunmuk),노선희(Noh, Seonhui),손민우(Son, Minwoo),정관수(Jung, Kwansue) 한국방재학회 2021 한국방재학회논문집 Vol.21 No.3

본 연구에서는 심화되고 있는 기후변화를 고려하여 보령댐 비상도수시설의 운영방법을 단순 Open-close release 형태에서 수자원의 효율적 이용측면에서 유리한 대응단계(관심, 주의, 경계, 심각)별 탄력운영방안에 대하여 연구하였다. 충남서부권지역의 보령시 지역을 대상으로 장래 기후변화 시나리오를 SWAT 모형을 이용하여 강수량과 유입량을 모의한 결과 결정계수 R2 값이 86.3%로 모형적합도가 적절한 것으로 확인되었다. 기후변화 시나리오 RCP 4가지와 SSP 2가지를 대상으로 유량변화를 적용한 보령댐 유역의 용수수급을 MODSIM으로 모의한 결과, 온실가스 저감정책정도에 따른 RCP시나리오 적용시 도수로의 탄력운영 적용방안보다 지속성장(친환경적 성장발전) 또는 고속성장(화석연료 의존 발전) SSP1-2.6, SSP5-8.5 시나리오 적용시 도수로 평균저수량이 39,600 m3/day, 39,900 m3/day로 적고 물부족 일수도 적게 나타났다. The Boryeong district, Chungnam western region, is well known as a chronic water-deficiency area; it is thus necessary to ensure that the operational system for the Boryeong Dam emergency facilities is sufficiently resilient to withstand the potential impacts of climate change, in particular irregular droughts with resultant low water inflows and low storage. This study was undertaken to determine the operational flexibility of the Boryeong Dam emergency diversion facilities and their ability to respond to water resources demand, even if the facilities have been operating on a simple open-close release rule, depending on dam storage levels. The precipitation and inflow in Boryeong district were forecasted according to the modelling of RCP (Representative Concentration Pathways) in combination with SSP (Shared Socio-economic Pathways) scenarios. This has led to recommendations for the flexible operation of the Dam’s diversion facilities in order to ensure a stable water supply based especially on SSP1-2.6 and SSP5-8.5; i.e., steady growth and dramatic growth scenarios were simulated. The result from these two scenarios was an average diversion rate of 39,600 m3/day and 39,900 m3/day, respectively. This was evaluated as reasonable water resource use because water deficit days were fewer, and the average diversion rate was less than the RCP scenarios.

Lower critical solution temperature (LCST) phase separation of glycol ethers for forward osmotic control

Nakayama, Daichi,Mok, Yeongbong,Noh, Minwoo,Park, Jeongseon,Kang, Sunyoung,Lee, Yan The Royal Society of Chemistry 2014 Physical chemistry chemical physics Vol.16 No.11

<P>Lower critical solution temperature (LCST) phase transition of glycol ether (GE)–water mixtures induces an abrupt change in osmotic pressure driven by a mild temperature change. The temperature-controlled osmotic change was applied for the forward osmosis (FO) desalination. Among three GEs evaluated, di(ethylene glycol) <I>n</I>-hexyl ether (DEH) was selected as a potential FO draw solute. A DEH–water mixture with a high osmotic pressure could draw fresh water from a high-salt feed solution such as seawater through a semipermeable membrane at around 10 °C. The water-drawn DEH–water mixture was phase-separated into a water-rich phase and a DEH-rich phase at around 30 °C. The water-rich phase with a much reduced osmotic pressure released water into a low-salt solution, and the DEH-rich phase was recovered into the initial DEH–water mixture. The phase separation behaviour, the residual GE concentration in the water-rich phase, the osmotic pressure of the DEH–water mixture, and the osmotic flux between the DEH–water mixture and salt solutions were carefully analysed for FO desalination. The liquid–liquid phase separation of the GE–water mixture driven by the mild temperature change between 10 °C and 30 °C is very attractive for the development of an ideal draw solute for future practical FO desalination.</P> <P>Graphic Abstract</P><P>Lower critical solution temperature (LCST) phase transition of glycol ethers by a mild temperature gradient induces a drastic change in osmotic pressure to enable energy-efficient forward osmosis (FO) desalination. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c3cp55467h'> </P>